Charles f



(No Model.)

0. F. ,SGOTT 8a A. WURTS.

LIGHTNING ARRESTER.

No. 470.013. Patented Mar. 1, 1892.

I INVENTORS: wnusssss: c4... Tye- 77- Zmz W UNITED STATES PATENT OFFICE.

CHARLES E. SCOTT AND ALEXANDER XVURTS, OE PITTSBURG, PENNSYLVANIA,ASSIGNORS TO THE \VESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, OFSAME PLACE.

LIGHTNING-ARRESTER..

SPECIFICATION forming part of Letters Patent No. 470,013, dated March 1,1892. Application filed July 1'7, 1891- Serial No. 399,875. (No model.)

To aZZ whom it may concern.-

Be it known that we, CHARLES F. SCOTT and ALEXANDER TURTS, citizens ofthe United States, residing in Pittsburg, in the county of 5 Alleghenyand State of Pennsylvania, have invented a new and useful Improvement inLightning-Arresters, (Case No. 466,) of which the following is aspecification.

The invention relates to the class of appa- Io ratus employed forprotecting electric circuits and machines from injury by reason of thedisruptive electrical discharges which are especially liable to occurduring the presence of thunder-storms.

Heretofore apparatus of various forms'have been employed for relievingthe lines comprised in an electric circuit from-static charges when suchcharges become exceedingly greatt-hat is to say, when the diiference ofpotential between the lines and the earth becomes excessive. This isusually accomplished by providing an earth or ground circuit for suchdischarges, in which circuit there is interposed an air gap or spaceacross which the disruptive discharges take place. The length of theair-gap must, however, be such that the normal electric currents usedupon the circuit shall not be of sufficient potential to overcome theresistance of the air; other- 0 wise these might themselves strike anarc and thus pass to the earth and short-circuit the generator. On theother hand, the distance must not be so great as to cause the dischargesto take place through the insulation of the ar- 3 5 mature of themachine or through some other portion of the circuit, rather than acrossthe air-gap. In other words, the resistance offered by the air-gap mustnot be greater than the resistance oli'ered by the insulation of the 40circuit. It is practicable to increase the airgap by at the sameincreasing the insulation of the entire system within certain limits butit is evident that these limits in this direction are soon reached.Various devices are also 4 5 employed for destroying the are formedacross the air-gap by the arc, so as to prevent the generated currentfrom following through the circuit thus momentarily established. Theobject of our invention is to provide means for effecting theequalization of the potential of the circuit with that of the earthcontinuously and without the occurrences of heavy discharges and alsowithout increasing the risk of short-circuiting the machines.

In an application filed by one of us (Alexander Wurts) on the 6th day ofJuly, 1891, Serial No. 398,503, there is described a method of drawingoff the static charge of a circuit at rapidly-recurring intervals, thuspreventing an accumulation of any undue amount and keeping the circuitin an approximately neutral condition with reference to the earth. Thepresent invention relates to the same general method and involvescertain details in the construction of the apparatus and the 6 5 meansfor carrying the method into operation.

The present invention consists in placing a discharge-plate inconnection with one side of an electric circuit and a second plateinconnection with the earth and in rapidly moving one of the plates towardand from the other, so that the discharges may take place from that sideof the circuit at frequent intervals. The other side of the circuit issimilarly organized; but the approach and separation of the plates ofthe two sides do not occur at the same time. The two sides of thecircuit are thus alternately discharged, and a temporary are formed fromone side to the earth would not result in a short-circuiting of themachine.

A convenient plan for carrying out the invention is to mount upon thearmature-shaft of the generator one or more discharge plates or combs,which may be connected with the earth or with the line, and in placingone or more corresponding plates or combs connected with the line or theearth, as required, in such position with reference to thearmature-shaft that those mounted on the latter will be alternatelybrought by the revolution of the shaft into proximity to the stationaryplates, thus allowing the discharges to take place from the differentsides of the circuits at rapidly-recurring intervals. As already stated,it is desirable that the discharge should be 5 allowed from only oneside of a circuit at a time, so that the danger of short-circuiting themachine is lessened.

In the accompanying drawings, Figure 1 is a side view of aportion ofamachine equipped with the discharging apparatus and showing circuits indiagram. Fig. 2 is a detail.

Referring to the figures, A represents the armature-shaft of an electricgenerator of any suitable character. It is mounted in suitable bearingsB. A-commutator or collector O is mounted upon the armature-shaft. Thecollector shown in the drawings comprises two insulated rings 0' cseparated by an insulating-ring E. The collector-brushes d d arerespectively connected with the main lines L L At suitable places-as,for instance, upon the ring E-there are mounted two sets of serratedplates or combs 6 6 each set being designed to constitute one side of alightning arrester or discharge device, the other side of which consistsof one or more plates e, connected with the earth at G throughaconductor Z. The plates e are placed in connection with thecollecting-ringc and the plates 6 with the ring '0 and they alternate inposition around the armature-shaft. The plate 6 is placed in suchposition that the rotation of the armature-shaft will cause the plates ee to be alternately brought into proximity with the stationaryground-plate in rapid succession. The nearness with which the plates areallowed to approach is governed in any instance by the insulation of thesystem or the electro-motive force which it is designed to normallyemploy upon the system, or by the amount of static charge which it isdeemed permissible to allow to accumulate on the circuit beforedischarging.

It will be understood that as any given plate 6' or e is, by therevolution of the armature, brought opposite the plate 6 a discharge maytake place from the correspond-i ing line L or L through thecorresponding brush and collector-ring and thence to earth across theintervening space. The positions of the plates are such with referenceto each other as to permit the revolving plates to come opposite theearth-plate in alternation. The position of the plate e may be madeadjustable toward and from the center of revolution of the platese' e inany suitable manner-as, for instance, by a screw h-and itscircumferential position may be adjusted by a screw h, passing through aslot m, Fig. 2, in its support, or in any other suitable manner.Additional ground-plates e may be employed, as indicated by dottedlines, if desired.

It is evident that various diiferent forms of devices and arrangementsof apparatus may be employed for carrying out this invention; but thatalready described will serve to clearly disclose the invention. 7

It is evident that the revolving or movin tator-rin gs.

We claim as our invention- 1. The combination, with an electric circuit,of one or more discharge-plates connected with the conductors of saidcircuit and one or more movable discharge-plates brought into proximitywith the first-named plate or plates in rapidly-recurring succession,substantially-as described.

2. The combination, with an electric circuit, of a discharge-plateconnected with one side of said circuit and a second dischargeplateconnected with the earth and apparatus bringing said plates intoproximity at rapidlyrecurring intervals.

3. The combination, with an electric ma- I chine having a revolvingarmature, of a discharge-plate carried upon or moving with the shaft ofsaid machine and a second dischargeplate placed near the path of thefirst-named discharge-plate, substantially as described.

4:- The combination, with an electric machine having a revolvingarmature, of a discharge-plate carried upon or moving with the shaft ofsaid machine, a second dischargeplate placed near the path of thefirst-named discharge-plate, a connection from one of the plates withthe earth, and a connection from the other plate with one terminal ofthe machine.

5. The combination, with an electric machine having a revolvingarmature, of one or more discharge-plates carried upon or moving withthe shaft of said machine, a dischargeplate placed near the path of thefirst-named discharge-plates, a connection from the lastnamed plate withthe earth, and a connection from the first plate with one terminal ofthe machine, said, plates being adjustable with reference to each other.

6. The combination, withadynamo-electric generator, of one or moregrounded dischargeplates, discharge-plates carried upon the shaft of thegenerator and revolving therewith and brought into proximity with thefirst-named plates by the revolution of the armature-shaft, andconnections from said second plates with the respective terminals of themachine, substantially as described.

7. The combination, with the plates of a commutator or collector, of twodischargeplates or series thereof carried by the armature-shaft, saidplates or series of plates being respectively connected with therespective commutator or collector plates, and one or more correspondingdischarge-plates placed in proximity to the path of revolution of thefirst-named discharge-plates and electrically connected with the earth.

In testimony whereof We have hereunto subscribed our names this 14th dayof July, A. D. 1891.

CHAS. F. SCOTT. ALEXANDER WURTS.

Witnesses:

F. E. J LITOT, J. 'W. SMITH.

